<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <ul id="ul">
    </ul>
</body>
<script>
    let ul = document.getElementById("ul");
    ul.innerHTML = "<li>1</li><li>2</li><li>3</li>";
    // js还可以发送ajax异步请求
</script>
</html>